To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
Meanwhile, the wireless communication technology has recently achieved rapid development, and therefore the communication system technology is also evolving. In recent years, various techniques have been introduced to meet the explosive traffic demand in the wireless communication system, and one of them is carrier aggregation (hereinafter, interchangeably used with CA or frequency aggregation). Contrary to a typical technique of using only a single component carrier (CC) for communication between a terminal (interchangeably used with user equipment (UE), etc.) and a base station (interchangeably used with E-UTRAN NodeB, eNB, etc.), the CA technique further uses a main carrier (interchangeably used with primary cell (PCell)) and one or more subcarriers (interchangeably used with secondary cell (SCell). Accordingly, the CA technique can dramatically increase the transmission amount by the number of added subcarriers.
However, in the LTE system or the 5G system, a predetermined bandwidth is defined for the base station to operate. Therefore, the carrier aggregation using a carrier (or a carrier band) corresponding to a bandwidth other than the predetermined bandwidth is impossible, and this may incur the waste of frequency resources. Accordingly, there is a need for a method of providing carrier aggregation using a carrier corresponding to a bandwidth other than the predetermined bandwidth.
In addition, since a control signal such as a synchronization signal necessary for access should be always transmitted even in the predetermined bandwidth, there is a limit to increase data transmission efficiency. Therefore, a method for solving this problem is also needed.